The proposed research describes a mentored training program in neuroendocrine regulation of metabolism, designed to provide the candidate the necessary skills and resources that will allow him to achieve the long- term goal of developing a career as an independent neurobiologist at a research-oriented university. Department of Medicine at Mount Sinai School of Medicine has well-established programs with state-of-the-art analytical instrumentations. The primary mentor, Dr. Christoph Buettner, is an established investigator and is well respected in the field of energy metabolism, while the co-mentors are authorities in metabolomics, gut- brain communication and bariatric surgery, and metabolic syndrome. The abundant institutional resources and excellent mentorship from these experts will provide an ideal training environment for the candidate to develop independence. The research plan focuses on central insulin action and its role in the regulation of branched- chain amino acid (BCAA) metabolism. Combining physiological and metabolic targeting tools with genetic, pharmacological, and surgical approaches, the experiments described in the proposal will identify: (1) the role of hypothalamic insulin on circulating BCAAs and their intermediates; () hepatic BCAA catabolism as controlled by the central insulin action; and (3) systemic and liver BCAA metabolism affected by Roux-en-Y gastric bypass (RYGB) surgery, and the potential role of central insulin action after RYGB. The proposed studies will advance our understanding of BCAA homeostasis that is under the control of hypothalamic insulin, and explain how this is perturbed in obesity and diabetes. Importantly, identifying central insulin action as a mechanism through which RYGB successfully improves BCAA metabolism holds promise for future development of non-invasive pharmacological treatments that mimic the surgery-induced effects.